Process of producing very thin sheet metal.



PATENTED FEB. 25, 1908.

T. A. EDISON. PROCESS OF PRODUCING VERY THIN SHEET METAL.

APPLICATION FILED JUNE 29, 1904.

2 SHEETS-SHEET 1.

\ Inventor Witnesses Attorneys.

T. A. EDISON. PROCESS OF PRODUCING VERY THIN SHEET METAL.

APPLICATION FILED JUNE 29. 1904.

PATENTED FEB. 25, 1908.

Wltnesses I V 1 2 SHEETS-SHEET 2.

Inventor Attorneys.

' the original cost of the bulk UNITED STATES-PA THOMAS A. EDISON, or LLEWELLYN PARK, ORANGE, NEW JERSEY, AssI'oNoRro Em N:

irnron;

STORAGE BATTERY COMPANY, OF WEST ORANGE, NEW JERSEY, A CORPORATION OF NEW I I JERSEY.

rat. 880,48.

rnocnss or raonccme vsnr'mm smar- Speciflcation' of Letters Patent;-

Patented Feb. at, recs:

AppHcationfiIei-Tune 29,1904. Serial No. 214.661.

To all whom it may concern:

Be it known, that I, THOMAS A. EDISON, a citizen ofthe United States, residing at Llewellyn Park, Orange, Essex county, State of N ew Jersey, have-invented acertain new anduseful Improved Process for Producing, Very Thin Sheet Metal, .of which the following is a description.

My invention relates to an improved method, or process, for producing ribbons of sheet metal of extreme thinness at lowcost. At the resent time, the only method in practice of metal is by the use of heavy-rolls, which gradually reduce the billet to the desiredthinness.

I am of course, aware that for the productionof gold foil, and other metal foils, beating operations with hammers are followed, but such a process is necessarily con fined within a verylimited field, and cannot compete in cost of roduct, with the rolling operation. In a rolling process, the reductron in thickness, which ma be efiected at each pass between the rol s, is relatively small, and in case of 'most useful metals, is limited by the loss in ductility, caused by continued change of its shape. Consequently, in rolling metals, it becomes necessary to restablis. the ductility by annealing the material, and eventuallyremoving the scale of oxid formed during the annealing operation. For this reason, the cost per pound of rolled sheet metal increases very rapidly as the thickness. or" the sheet decreases, so that in case of very thin sheets, material forms only a small fraction of the cost'of the completed roduct. repeats and expensive rolling, annealin and reducing operations, and to obtain. d1- rectly from a chea raw material, a roduct of the desired thic ness and shape, cause the metal to be de osited out-0f an electrolyte upon a suitab le cathode, the surface of which possesses the propert deposit, when it has reac ed the desired thickness, to be readily and continuousl detached without injury either to the cat ode or to the deposit itself. In this way,- the cost of the product is directly roportional to its weight, and is determined y the price of the raw material and the cost of the operations followed. Hence, in dealin with any particular metal, it becomes possible to use for manufacturing thin sheets In order to avoid theseof allowing thedetermine a particular thickness of. sheet Whioh'c'anbe obtained for the same cost by my improved process ,or by the usual rolling; process; so that in malt-in thicker sheets, a' rolling process willbe pre erable on'account of'cheapness, while in making thinner-chaste;

the product can be more economically oh-' tainedby my improved; process and-apparatus. Maniiestly'the economiessecured by" caplryingmy improved process into efiect' W1 which the two processesare on substantially the same footing as-to cost of'operation:

As the result of very extensive ex ssh merits, I'have found that surfaces from w ioh be relatively increased-in making. sheets' that are materially thinner than that at.

ametallic electrolytic depositmay be as readily and cleanly stripped, may be formedof-a number of metals, such as iron, copper, nickeland silver, ifin a'hig-hly polishedcondition, and especially when there is present a microscopic layer, of iorei n matter, like oxids, grease or graphite. find, however, that this pro erty is possessed to a'superior" and remarka its alloys. With these materials, I attribute the special scale of .OXl tnat in all solutions'forms upon the surface of aluminium and its alloys, and which is instantaneousl regenerated ifruptured, permits the rea y tion of the deposited metabfrom-a-cat ode formed of aluminium or its alloys.- With pure aluminium, this tendency of forming an oxid is so strong, that a moments exposure to air, or a short interruption of the currentallows the formation of a prohibitively large amount of OXlCl for'securmg a good deposit; and for this reason I prefer to employ an alloy of aluminium instead of the ure metal. I have obtained excellent resu ts in practice with an alloy consistin of 95 percent. ofcop per and 5 per cent. of a uminium.

le degree by aluminium andand clean so ara- In carrying my invention into effect, I may I secure the deposit u p which the deposits films are stripped intermittently, but preferably, I employ an endless surface moving slowly throu the electrolytic bath and upon which t e continuousl deposited and 'from which the de osited fil m is being continuously stripped ofl so that-the process is a continuous one and may be earned out for the production of metallic films many hundreds of' ,feet in length. Such an endless surface may be preon separate sheets, from metal isimproved method, and

. tially equidistant therefrom, and preferably.

'stitutes the catho e, nected to the pro er source of by means of asented by an endless metallic belt, running over rollers of large diameter, and receiving a metallic deposit on one or both of its sides, but I preferably employ a drum for this purpose, presenting a smooth outer surface on which the deposit takes place.

In order that understood, attention is directed to the accompanying drawings forming a part of this specification, and inwhich Figure 1 is a longitudinal sectionalviewlof an apparatus suitable for the practice of my Fig. 2, a partial sectionalview of the same on a larger scale.

In these views, corresponding parts are represented by the same numerals of referonce.

The tank 1 is made of any suitable insulating material, such as wood or slate, and is of the desired capacity. Mounted to rotate in this tank is a drum, formed of disks 22, and with its cylindrical portion 3 havinglflanges 4-4 The cylindrical portion 3 of t e drum is insulated from the disks 2-2 thereof by a rubber insulator 5, interposed between the flanges 44 and said disks, as shown. The

drum as a whole, is assembled upon a sleeve 6, on which'are mounted nuts 77, between which the disks are clamped. One bearing for the drum is formed by a pin 8, engaging the socket 9 on one of the side walls of the tank, and the other bearing is formed by a hollow shaft 10, which passes through a stufi-' ing box 11 to prevent leakage around said shaft. The shaft is rotated in any suitable way, as .by power connections en aging the sprocket is of such a character that the drum is rotate with eatslowness, and I have successfully experimented with apparatus for the purpose v in which the peripheral speed of the drum is about one foot in thirty minutes.

The cylindrical ortion 3 of the drum conand is electrically. consupply 1n any suitable wa as or exam le, contact dis -13, carried y the end of the shaft 10, but insulated therefrom, and dipping in a mercury cup 14, having a binding post 15, by which the proper connection is made. The contact disk 13 is connected electricall .to the cylindrical portion 3 of the drum y one or more insulated wires 16.

The an'odes17 are preferablybars of metal, which is to be deposited; extending, artly around the drum, as shown, and su stansupplemented by auxiliary anodes 18, arranged as shown, in rder that the deposit may continue onto the strip after the'latter has been stripped from the drum, and so long as it may remain in the solution; The anodes 17. and auxiliary anodes 18 are supported'irom the metal bars 19, with which the proper electricalconnections are made.

the invention may be better example,

wheel 12. In practice, t e gearin top thereof.

and will be ssonsa The stri after being removed from the surface oft e drum is accumulated in any suitable way, as for example, being wound up on a drum 2O rotated by any ap ropriate. mechanism. I find in practice t at the results obtained are materially improved by keeping the solution in a heated condition, and this is especially true in making thin strips or sheets of iron. This heating of the solution. may be efiectedin any suitable way, as for by a steam coil 21. In some instances also, should be kept in agitation during the electrolytic operation in order to prevent the de osit of insoluble matter, as well as of gas bu bles on the drum, or other surface on which the metal is to be deposited, and for this purpose any suitable agitating devices may be made use of.

Although my improved method is capable of efiective use in connection with the making of sheets, or films, of various metals, I have designed it particularly for producing sheets, or films, of iron or steel, or of ironnickel alloys, or nickel alofieyand in order that the method may be understood by those skilled in the art, I will describe itin connection with the production of iron films. A For this purpose a 20 per cent. solution of ferrous and ammonium-sulfate isemployed, mainit is desirable that the solution tained at a temperature of about 85- degrees centigrade throughout, and kept at substantially a constant density. v

' The anodes 17 and uxiliary anodes 18 are composed of metallic iron. The solution is maintained in the tank 1 quite close to the Upon closing the circuit between the anodes, auxiliary anodes, and the drum, and by rotating the drum ver'y slowly as explained, the metal will be homogeneously deposited on the drum at a rate depending obviousl upon the current density, and upon the sur ace s eed of the drum. By making the c lindrica portion 3 of the drum of big ly poished metal, and particularly of an alloy of copper and aluminium, as explained, the deposit may be. stripped from the drum to form a continuous uninterrupted film 22, which is applied to the reel 20 and wound upcontinuously thereon. Afterthe stri 22 leaves the drum, it is subjected to an ad itional de osit on each side between the anodes 17 an auxiliary anodes 18, as will be understood. In practice, it will be of course obvious that. the deposit will commence to form on the drum immediately in advance of the line at which the strip leaves the drum gradu'allyincreased in thickness, as the deposit continues, the rate of increase being augmentedafter' the strip leaves the drum, because-at that time the deposit "will take place on both sides of'the strip; If the entire deposit isse'cur'ed on; the cathode it will be understood ofcourse that the auxiliary anodes 18 may be omitted. Inthe lat-- 80111131011 which might contaminate the surface to require a separate washing.

I find that by carrying my imp'roved method into effect I obtain a product which even before annealing is very tough and workable, while, when annealed it com ares favorabl with the very best of stee and iron, an is practicall free from carbon and other elements. I have practically used my improved process in the make-up of my iron-nickel storage battery, wherein active materials are malntained under'pressure in perforated pockets composed of thin sheet steel, and for this art, I am enabled to r0- duce sheet metal having the/desired char-- acteristics at less cost than by the ordinary rolling operations. It will, however, be understood that other metals may be worked in this way for the production of sheets of any desired-degree of thinness and that foil can be obtained which will compare favorably with foil now secured by beating operations.

Having now described my invention, what I claim as new therein, and desire to secure by Letters Patent, is as follows:

1. An improved process for producing metallic sheets or foils, which consists in electrolytically depositing a thin metal film on the deposited film from said cathode of an aluminium-copper alloy in which the percentage of copper largel predominates, and in finally strippmg the fi m from said surface, substantia ly as set forth.

2. The process of producing thin sheets or foils of iron, which consists in electrolytically (1e ositing iron from an iron solution upon a olished surface of an aluminium cop er aloy in which the percentage ofcopper argely a polished surface predominates, and finally in stripping the deposited film from said surface, as set forth.

3. An improved rocess for producing metallic sheets or foilg which consists in electrolytically depositing a thin metallic film upon an endless polished cathode, in continuously movingsaid cathode in the electrolytic bath and in continuously stripping elow the surface of the bath, substantially as set forth.

4:. An improved rocess for producing metallic sheets or foi s which consists in electrolytically depositing a thin metallic film upon an endlesspolished cathode situated entirely below the surface of the electrolytic bath, in continuously moving said cathode in the bath and in continuously strip ing the deposited film threfrom, substantia i; as set forth.

This specification signed and witnessed this 24th day of June 1904.

THOS; A. EDISON substantially Witnesses:

FRANK L. DYER, MINA 0. MACARTHUR. 

